Such a piston machine is known from DE 10 2004 043 745 B3.
The hollow of the piston is advantageous, as it reduces the mass of the piston, when compared to a massive piston. When, however, such a piston machine is used as a pump for water, it can be observed that cavitations occur in the hollow. It is assumed that the underpressure gets too large, as the fluid cannot be moved fast enough.